RGB is about light in the darkness. No light: no color. By controlling the ratio of Red, Green, and Blue, we can create any color we want! Where both red and green light overlap, we get yellow. Green and blue combine to make cyan. Magenta is the total of red and blue. All three make white.
It’s often useful to note which color is absent or lacking. For example, cyan is the absence of red. Or if an image looks too magenta, we add a bit of green.
It gets tricky when we try to express how much of each we want. With most software, we use numbers between 0 (no light) and 255 (the maximum). The RGB value of 0 0 0 is black—all lights ...